Internal structural configurations of bladders used in patient support systems

ABSTRACT

A bladder comprising an outer and inner surface having a length, height and width, first and second ends, and an internal volume. A support structure is disposed within the bladder and has a length, width, height as well as an inner and outer region. The outer region of the support structure comprises support projections which define openings in the outer region of the support structure. The support projections have an engaging end which contacts the inner surface of the bladder and exerts force upon the inner surface of the bladder. The support projections maintain the internal volume of the bladder in a no-load sate. The openings in the support structure allow air to move freely in the bladder versus a solid support structure lacking openings. This aids in distribution of air within the bladder and provides air-like pressure management and comfort in addition to the structural support provided by foam inserts.

PRIORITY CLAIM

This application claims the benefit of previously filed U.S. Provisional Patent Application entitled “Internal Structural Configurations of Bladders Used in Patient Support Systems,” assigned U.S. Ser. No. 61/176,555, filed May 8, 2009, and which is incorporated herein by reference for all purposes.

FIELD OF THE INVENTION

This subject matter generally relates to internal structural configurations for bladders used in support surfaces for preventing, reducing, and/or treating decubitus ulcers, also known as pressure sores or bedsores.

BACKGROUND OF INVENTION

The present subject matter generally relates to bladders and air cylinders used in patient support surfaces and more particularly to combinations of foam and air or fluid technologies which are selected so as to lend themselves to certain common modular assembly features, in the context of improved performance and/or costs.

Particularly in the field of healthcare, there has been a long felt and profound need to provide pressure relief for immobile or otherwise confined patients. For a tremendous variety of reasons, many patients must withstand long periods of bed rest or other forms of confinement, such as use of a wheelchair or other accommodating but restrictive support arrangement. In those instances, there is a tremendous risk that exposure to excess pressure, or longer term exposure to relatively lower pressure levels, can result in painful and even dangerous sores and other conditions in addition to decreased oxygen uptake, loss of bone mass, loss of skin integrity, loss of appetite, and decreased cardiovascular functioning.

Literally an entire segment of the healthcare industry is directed to the study and treatment of various tissue traumas, such as decubitus ulcers. Tissue damage can be monitored and rated, with progressively higher ratings warranting more involved treatment approaches. For example, the Braden Scale is an assessment tool for determining a patient's risk level for incurring skin breakdown. Consequently, the healthcare industry perceives and evaluates treatment options on the basis of their ability to address conditions at such different stages or ratings.

Healthcare costs, generally, as well as patient well being may be greatly affected by the degree of pressure relief for patients confined to beds for significant periods of time. Pressure sores (e.g. decubitus ulcers), potentially leading to infections and other worsened conditions or complications can occur from prolonged pressure exposure, such as experienced by those confined to beds, whether in a hospital, nursing home, or private residence. Considerable efforts have been made to provide mattress systems or patient support surfaces which effectively redistribute and equalize pressure forces at the interactions between the patient and the support surface. Generally speaking, the more sophisticated techniques for achieving such pressure reductions are relatively more involved and therefore more expensive to manufacture and/or use. Certain generally effective techniques involve the use of elongated air tubes or cylinders variously combined with foam pieces. Examples of embodiments having a plurality (such as four) of generally longitudinal elongated air tubes are set forth in commonly owned U.S. Pat. Nos. 5,070,560 and 5,412,821. Such patents include the use of relatively stiffened lateral slats to help convey and redistribute forces laterally from one air tube to another. Such redistribution takes place over relatively limited areas of contact between the respective elements. While such approach is generally effective, one aspect of the present subject matter seeks to improve on the redistribution and equalization of pressure forces in the context of using such elongated air tubes and to otherwise improve the function thereof.

Typically, various support systems have made use of resilient support bodies, such as strips or blocks of foam, or some other support bladder containing a specific fluid. Mattress technologies, in general, have often made use of other resilient support media, such as springs, slats, or various support fillers, such as ticking. Different gases, often such as air, or various liquids have been used, including relatively viscous liquids, such as gels. In some instances, combinations of the above various technologies have been used.

One aspect of support systems, especially concerning those for use with recumbent patients, is that they are faced with distinctly different loading requirements along the longitudinal axis thereof. In other words, certain body areas of a patient will be heavier than others, thereby generally requiring greater support in such longitudinal areas if pressure relief is to be optimized.

As a result, various support pads have sought to provide sectionalized support. One such resilient foam pad making use of a uniform patterned surface, though with differential resilient support responsive to different loads, is U.S. Pat. No. 5,007,124 entitled “Support Pad with Uniform Patterned Surface.”

As foam surface patterns become more sophisticated, there is a corresponding increase in the difficulty of producing such articles. One example of a three section foam mattress is U.S. Pat. No. Des. D336,400, entitled “Foam Mattress Pad.” Another example of a still more complicated foam mattress surface, typically requiring a computer controlled cutting machine for production, is U.S. Pat. No. 4,862,538, entitled “Multi-Section Mattress Overlay for Systemized Pressure Dispersion.”

Still further examples of various resilient foam support pads and the like, and certain aspects of manufacture thereof, are shown by U.S. Pat. Nos. 4,603,445; 4,700,447; Des. D307,688; Des. D307,689; Des. D307,690; 5,025,519; Des. D322,907; and 5,252,278. Generally speaking, as support surface designs become more entailed, they become more difficult and more expensive to produce. At the same time, regardless of the manufacturing cost, they provide a generally static or preset response to loading changes, i.e., changes in the weight of the patient being supported in a specific region of the pad. Such variations may occur due to the variations among patients, or simply to the movement of an individual patient.

One example of a pressure relief support system utilizing fluid filled chambers is shown by U.S. Pat. No. 5,070,560, entitled “Pressure Relief Support System for a Mattress.” In such patent, sealed longitudinal air cylinders are provided in the shape of a mattress, otherwise having various transverse slats and/or foam strips or members. Such a support system offers air dispersion pressure treatment in a static design which avoids the relative extremely high cost and other negative factors often associated with active air bed systems.

Highest rated pressure relief support systems typically involve beds having a plurality of fluid filled chambers, the internal pressures of which are maintained at a constant pressure by a relatively higher technology dynamic system approach. Specifically, each fluid filled support element may be associated with its own control valve, alternately permitting ingress and egress of fluid. Various pressure sensitive detection devices typically may be utilized in a feedback control system for determining that an excess pressure condition (or a subpressure condition) exists. Thereafter, the control technology is operative for bleeding off excess pressure by selected valving operation (such as dumping excess fluid into a reservoir arrangement) or for actively pumping in additionally needed fluid.

As such, the above higher technology systems require various motors, pumps, valving systems, sensory feedback arrangements, and control systems for all the foregoing. Due to their complicated construction and design, such beds are typically more expensive with respect to initial purchase or rental cost. They can also be complicated and expensive to maintain due to the prospect of failure of numerous moving mechanical parts, and due to the extensive training which an operator or maintenance person would be required to undergo.

Also, there is the prospect of highly undesired heat transfer to a patient, due to operation to the above-referenced motors, pumps and other systems. Still further, the construction and design of such overall systems often require specialized bed frames not otherwise usable with typical mattresses.

Typically, air or fluid flows among the bladders disposed in a patient support surface in response to the weight of the body to equalize pressure throughout the system, provide a constant, uniform distribution of safe pressures beneath the patient, and prevent bottoming out of the support surface. The bladders are air or liquid filled, as discussed above, or may be a bladder with a foam insert such as those described by Giori et al. in U.S. Pat. No. 6,922,863, Michiels in U.S. Pat. No. 4,407,031, Bondie et al. in U.S. Pat. No. 6,588,038, Stinson et al. U.S. Pat. No. 5,388,292, Stolpman et al. US RE38,135.

The existing bladders used in patient support platforms, either air, liquid or air/liquid/foam filled, while providing a surface for a patient, have various failings. Air or fluid filled bladders achieve, through volume modulation, a very soft feel for the user. However, air or liquid filled bladders are subject to deflation if pierced while in use as well as “hammocking” or “bottoming out” wherein the patient comes to rest on the substrate beneath the bladder due to insufficient support. The problem with pressurized air supported surfaces is that if air were allowed to escape the pressurized chamber, the support surface would collapse and cause a hammock effect.

Bladders that use foam inserts within an air filled bladder fail to provide the measure of comfort associated with an air or liquid filled mattress. Foam adjusts to the patient's body's pressure points locally by the density of the foam increasing as the foam is compressed by pressure from the patient's body. Further, too soft of a foam can mimic the hammock or bottoming out experienced with air or liquid filled bladders. Moreover, the foam inserts impede the flow of air through the bladder, thus preventing or significantly slowing the ability of the support surface to adjust to the patient. Also, an undesirable characteristic of open-cell flexible polyurethane foam is that it can potentially solidify in a full vacuum-state, a so-called ‘compression set’ (CS). If too much air is removed from the cellular structure of foam, it will harden in its densest state and subsequently no longer be able to self-inflate and regain its loft, even partially. CS becomes critical when foam has been compressed for an extended period of time.

There exists a need for a simplified design for bladders or air cylinders used in patient support systems which give the clinician the needed options in addressing integrity of the skin and deep tissues. A need exists to provide a bladder which is simple to construct as well as providing a method of equalizing pressure over the surface of the body by means of interconnected air-filled tubes that shift air from tubes under more pressure to tubes under less pressure. This allows greater immersion of the body into the mattress, which decreases pressures under any single point, and distributes pressures over as great an area as possible. There also exists a need to combat the aforementioned failings associated with air filled, liquid filled and air/liquid/foam filled bladders by providing a bladder that combines the support and comfort of an air or liquid mattress with the structural support provided by a foam insert without diminishing the ability of the patient support surface to rapidly adjust to pressure changes.

The disclosure of all U.S. patents noted in this application, above or hereinafter listed, are fully incorporated herein by reference to the extent not inconsistent herewith.

SUMMARY OF THE INVENTION

The present subject matter recognizes and addresses various of the foregoing problems, and others, concerning the bladders or air cylinders present in patient support surfaces. Thus, broadly speaking, a principal object of this subject matter is improved patient support surfaces via improved bladders. More particularly, a main concern is improved patient support surfaces of the type involving bladders or air cylinders using combinations of foam and air or liquid technology. Such patient support surfaces are provided for receiving a patient thereon, and have at least one adjustable fluid support bladder with fluid therein. Multiple fluid support bladders may be used in additional embodiments and various forms of foams and fluids may be practiced throughout all such embodiments.

The present subject matter is directed to a bladder comprising an outer surface, an inner surface, a length, a height, a width, and first and second ends. The bladder has an internal volume. There is a support structure disposed within the bladder wherein the support structure comprises a length, a width, a height, an inner region, and an outer region wherein the outer region of the support structure comprises support projections which define openings in the outer region of the support structure. The support projections have an engaging end which contacts the inner surface of the bladder and exerts force upon the inner surface of the bladder to maintain the internal volume of the bladder in a no-load state. A no-load state is the condition of the patient support surface when a patient is not present on the surface.

In one exemplary embodiment, the support structure comprises less than 90% of the internal volume of the bladder. In other embodiments, it may comprise less than 80% whereas in further embodiments it may comprise less than 70% or even less than 60%. In one preferred embodiment, it may comprise about 80%. More broadly, it is to be understood by those of ordinary skill in the art that the present subject matter is intended as having a foam-to-air ratio relatively as low as possible while still being able to have the foam component to restore the unloaded volume of the tube. So, for various embodiments depending on their specifics, it is understood that such ratio will vary.

An exemplary support structure in accordance with the present subject matter can be a single piece or multi-piece construct with support projections extending outward from the inner region. The support structure may extend the full length of the bladder or extend only partially along the length of the bladder. In another embodiment, there is more than one support structure enclosed within the bladder. In still another present exemplary embodiment, the inner region of the support structure defines a cavity in the interior of the inner region. In still another exemplary embodiment, the inner region of the support structure defines more than one cavity in the inner region of the support structure. The cavities can extend partially or entirely through the length of the support structure.

With respect to the support projections, these may extend radially outward from the inner region. In one embodiment, there are at least three support projections extending from the inner region. In other embodiments, more than three, such as four, fix or six or more support projections extend from the inner region. In accordance with the present subject matter, the spacing of the support projections with respect to one another can vary. They may be spaced evenly apart with respect to one another or they may be randomly spaced with respect to one another.

In yet another embodiment, the bladder has support projections comprised of a base which is integral with the inner region of the support structure, a body which has a length and extends away from the base, and the engaging end has a terminal area which engages the inner surface of the bladder. In further embodiments, the support projection may have a uniform width along substantially all of its length. In other embodiments, the support projection may taper along its length toward the terminal point.

In another embodiment, the terminal area on a support projection can be a point, a convex rounded surface, a concave rounded surface, a flat surface, or combinations thereof. Moreover, different support projections may have different terminal ends. For example, in an embodiment with six support structures, three could have terminal areas that are points, one a concave rounded surface and two flat surfaces in order to aid with defining the structure of the bladder.

In yet another embodiment, the bladder is in a patient support surface and has an exterior, an interior, a length, a height, a width and first and second ends. The bladder is flexible and can expand and contract. There is a support enclosed within the interior of the bladder. The support may comprise an inner core and outer projections extending radially from the inner core. The outer projections may define a space between each outer projection and the next adjacent outer projection. The outer projections may each have engaging ends which engage the interior of the bladder and keep the bladder expanded by exerting an outward force when the bladder is in a no load state.

In yet another embodiment, there is a modular patient support assembly comprising plural patient support air cylinders. The air cylinders comprise an outer surface, an inner surface, a length, a height, a width, first and second ends. The air cylinders have an internal volume. There is a support structure disposed within the air cylinders wherein the support structure comprises a length, a width, a height, an inner region, an outer region wherein the outer region comprises support projections which define openings in the outer region of the support structure. The support projections have an engaging end which contacts the inner surface of the air cylinders and exerts force upon the inner surface of the air cylinders and maintain the internal volume of the air cylinders in a no-load state. There may be a resilient foam perimeter surrounding said air cylinders and supplemental inner bolsters provided within an inside perimeter defined by said resilient foam perimeter. There is also an upper foam topper covering said air cylinders and including underside multiple curved projections interoperative with said air cylinders for positional stabilizing. A surrounding cover may also be utilized.

Another present general object is to provide a fully self-adjusting pressure relief system which optimizes pressure dispersion, while still using a relatively inexpensive and simple designs so as to obviate the need for motors, control systems, or specialized bed frames or training associated with its use and, maintenance.

Yet another object is to provide a pressure relief support system which is self-adjusting to allow for more even body weight distribution, thereby improving the reduction of pressure on the tissue and skin of a user. At the same time, it is an object to provide a self-adjusting technology which may be customized, as desired, for different patient uses, and for different alternate uses.

More specifically, it is a present object to provide a self-adjusting pressure relief technology which is usable with virtually any type of fluid (gas, liquid, relatively viscous liquids), and which is usable in a variety of settings. Specifically, it is intended to provide such self-adjusting technology usable in both medical and commercial fields, including both mattress-related technologies and seating technologies, as well as others. In the area of medical uses, it is intended to provide a system and improved technology which is usable in space critical circumstances, such as involving X-ray, operating room, or NMR technology uses. It is intended for the present technology to be equally applicable to critical care situations, emergency room gurneys, ambulance stretchers, and medical seating systems of all types, such as wheelchairs or geriatric chairs.

It is another present object to provide a self-adjusting technology with the advantages of active (i.e., dynamic) fluid-based systems, but with such simplicity that the technology may be extended to every day consumer products, such as ergonomic chairs and car seats, as well as consumer mattress replacement systems, mattresses and mattress overlays (as would also be applicable in the medical field).

It is a still further object of the present subject matter to provide a technology capable of being customized to provide specialized support surfaces, such as for pregnant women, or for amputees or other persons requiring nonconventional support needs for either sitting or sleeping or bed rest.

Still further, it is a present object to provide improved technology applicable in a broad sense virtually to any circumstance of bodies in rest. For example, such technology may be incorporated into specialized pillows, such as in the case of head injuries involving swelling or other weight changes. Likewise, the present technology would be equally applicable to packaging arrangements (such as for fragile equipment) where it is desired to minimize or limit pressures associated with transfer shock or the like.

One present exemplary embodiment relates to a patient support system for the prevention and treatment of decubitus ulcers. Such an exemplary patient support system may preferably comprise a foam shell defining an internal cavity; a plurality of air cells housed in such internal cavity; and a cover encasing such foam shell. With such exemplary arrangement, preferably such plurality of air cells respectively each comprises a bladder and an internal support structure comprised of resilient material and only partly in contact with such bladder.

Another present exemplary embodiment may relate to a patient support assembly, comprising plural patient support cylinders; a resilient foam perimeter surrounding such air cylinders; an upper foam topper covering such air cylinders; and a surrounding cover. Preferably, in such exemplary arrangement, such cylinders respectively include fluid and foam inserts having support projections supporting associated of such cylinders; and such cylinders are positioned one of generally longitudinally and generally laterally within such resilient foam perimeter.

In yet another present exemplary embodiment of the present subject matter, a support system may preferably include a plurality of fluid receiving cells, with each of such cells including at least one foam insert having internal support structure only partly in contact with an associated cell.

Additional objects and advantages of the present subject matter are set forth in or will be apparent to those of ordinary skill in the art from the detailed description which follows. Also, it should be further appreciated that modifications and variations to the specifically illustrated and discussed features, steps or materials hereof may be practiced in various embodiments and uses of this subject matter without departing from the spirit and scope thereof, by virtue of present reference thereto. Such variations may include, but are not limited to, substitution of equivalent means and features, materials or steps for those shown or discussed, and the functional or positional reversal of various parts, features, steps, or the like.

Still further, it is to be understood that different embodiments, as well as different presently preferred embodiments, of this subject matter may include various combinations or configurations of presently disclosed features, steps, or elements, or their equivalents (including combinations of features or steps or configurations thereof not expressly shown in the Figures or stated in the detailed description). Also, it is to be understood that various features from one embodiment; as illustrated, discussed or suggested, may be combined with or substituted for features of other disclosed or suggested embodiments, within the spirit and scope of the present subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present subject matter, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended Figures, in which:

FIG. 1 is an exploded view of a prior art device wherein representative bladders are shown in relation to other elements, collectively comprising a patient support surface;

FIG. 2 is a perspective view of a prior art device wherein representative bladders are shown in relation to other elements, collectively comprising a patient support surface;

FIG. 3A is a top plan view of a prior art device wherein representative bladders are disposed parallel to the user's body in a patient support surface;

FIG. 3B is a top plan view of a prior art device wherein representative bladders are disposed perpendicular to the user's body in a patient support surface;

FIG. 4 is a perspective view of one exemplary embodiment of the present subject matter, showing exemplary support structure and an enclosing bladder;

FIG. 5A is a perspective view of one embodiment of the present subject matter illustrating an exemplary support structure without an enclosing bladder;

FIG. 5B is a perspective view of another embodiment of the present subject matter, showing an alternative exemplary support structure without an enclosing bladder, where such exemplary support structure has a four point star cross-sectional configuration;

FIG. 5C is a perspective view of yet another embodiment of the present subject matter showing an alternative exemplary support structure without a bladder, where such exemplary support structure has a cog or gear-shaped cross-sectional configuration;

FIG. 5D is a perspective view of a further embodiment of the present subject matter showing an alternative exemplary support structure without a bladder, where such exemplary support structure has a cross-shaped cross-sectional configuration;

FIG. 6 is an end elevation view of one end of the exemplary support structure and bladder as shown in present FIG. 4, and illustrating engagement of such exemplary support structure with the interior of such exemplary bladder;

FIG. 7A is an end elevation view of one end of an alternative embodiment of the support structure and bladder as generally shown in present FIG. 4, wherein such exemplary support structure has support projections with convex shaped engaging ends, based on truncated projections; and

FIG. 6B is an end elevation view of one end of a further alternative embodiment of the support structure and bladder generally as shown in present FIG. 4, wherein such exemplary support structure has a five pointed star shaped support structure with pointed engaging ends.

Repeat use of reference characters throughout the present specification and appended drawings is intended to represent same or analogous features, elements, or steps of the present subject matter.

It is to be understood that the present language is by way of example and description only and is not intended to limit the broader scope of the present subject matter as otherwise disclosed herewith, including features as referenced in the Figures.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to presently preferred embodiments of the present subject matter, examples of which are discussed in conjunction with the accompanying drawings. Such examples are provided by way of an explanation of the present subject matter, not limitation thereof. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present subject matter, without departing from the spirit and scope thereof. For instance, features illustrated or described as part of one embodiment can be used on or in another embodiment to yield a still further embodiment. Still further, variations in selection of materials and/or characteristics may be practiced, to satisfy particular desired user criteria. Thus, it is intended that the present subject matter cover such modifications and variations as come within the scope of the present features and their equivalents.

Particularized definitions used herewith include:

ILD—Indentation Load Deflection or IFD—Indentation Force Deflection—measure of the stiffness of open-cell foam which measures conformability or ability to immerse the patient to distribute weight as well as measures the compressibility or the ability to support the patient and prevent bottoming out. Measured as the number of pounds needed to indent a 4″×12″×12″ sample of the foam with a 50 square inch circular plate a certain distance. 25% ILD/IFD—indents the foam 25% of the way through the sample, or 1″. 65% ILD/IFD—indents the foam 65% of the way through the sample, or 2.5″. No-Load State—the condition of the patient support surface when a patient is not present on the surface.

While in accordance with the present subject matter no particular measurements are contemplated as necessary or required with respect to the outward forced applied by the support projections on the inner surface of the bladder, the present subject matter does consider the “preload” on the star (or other design) tips based on the amount of interference between the tube diameter and the star “diameter”. For example, the present subject matter may encompass a range of designs, from the radius of the star being 10% larger than the radius of the tube to the radius of the star being 20% smaller than the radius of the tube, or even designs outside of such range. In general, those of ordinary skill in the art will appreciate that one of the trade-offs to be considered in any given embodiment is the level of functionality desired versus the desired cost of manufacturing for a particular foam-in-tube design, all of which variations are intended as being encompassed by the present disclosure.

Applicant hereby incorporates by reference, in their entirety, U.S. Pat. Nos. 6,782,574 and 6,223,369, to the extent not inconsistent herewith.

FIG. 1 is an exploded generally top and mostly end perspective view of a prior art patient support surface wherein a plurality of generally longitudinally-place bladders 100 are shown in relation to other elements comprising a patient support surface. U.S. Pat. Nos. 6,223,369 and 6,782,574 disclose a patient support surface into which presently disclosed bladders could be incorporated and are hereby incorporated fully by reference. Patient support surface 34 includes a foam topper 24 which may be integrally included within the patient support surface. Particularly, the upper support surface of such foam topper may include a variety of constructions designed and intended to facilitate pressure relief. Pressure relief, for example, may be provided by a number of lateral cuts or channels generally 26 formed in such surface as illustrated in solid line. Another aspect of the patient support surface is a pair of inner bolsters 68 and 70, which run longitudinally along the lengthwise axis of patient support surface 34. As illustrated, each inner bolster 68 and 70 has a respectively inwardly facing concave surface 72 and 74 which interacts with part of the curvature of respective air bladders 200. Still further, each concave face 72 and 74 is provided with at least one respective curved slot 76 and 78, respectively, therein, for purposes as further discussed below.

Patient support surface 34 also includes perimeter bolster components 16 and 18. These may be of relatively more dense material for relatively greater support than side or inner bolsters 68 and 70, which in turn may be of relatively greater density or firmer support than foam topper 24. As shown, a plurality of depending elements 82, 84, and 86 constitute projections which approximate inverted contoured triangles. Otherwise formed in the underside surface 80 of foam topper 24 are a plurality of downwardly facing arches generally 88, 90, 92, and 94. As will be understood by those of ordinary skill in the art, such respective arches run along the longitudinal length of foam topper 24 formed in the underneath side 80 thereof. Likewise, the underside arches interact and interface with the generally top sides of the respective bladders 100, such that the depending elements 82, 84, and 86 work into the areas between the respective bladders 100. The resulting combination cradles and surrounds the bladders, providing an interlocked, integrated design having flexible, progressive support while maximizing structural integrity. Such integrated structural integrity includes the beneficial tube capturing effects of the side or inner bolsters 68 and 70, as well as the beneficial effects of perimeter bolster 14 as shown by present FIG. 2.

FIG. 2 is a generally top and partial side perspective view, in partial cutaway, of a prior art patient support surface.

FIGS. 3A and 3B are respective top plan views of prior art devices, representing bladders 100 can be disposed parallel to the user's body in a patient support surface 34, or with bladders generally 102 disposed perpendicularly to the user's body.

It is to be understood that any of the various exemplary support structure and enclosing bladders disclosed herewith per present subject matter may be variously incorporated in place of bladders 100 and/or 102 of the foregoing exemplary patient support surfaces. Likewise, present exemplary support structure and enclosing bladders may be utilized in conjunction with other forms of patient support surfaces, or in other entire arrangements.

FIG. 4 is a perspective view of one embodiment of the present subject matter showing an exemplary support structure 216 and a representative enclosing bladder 200. It is to be understood that the various exemplary support structures of the present subject matter may be utilized in conjunction with such enclosing bladders, as desired for different present embodiments, all of which in turn may be used in the representative patient support surfaces described herein, or in other combinations.

The exemplary support structure generally 216 of present FIG. 4 can be formed from any suitable composition including foam, plastic, meltblown or spunblown materials or other suitable structural materials known to those skilled in the art. One presently preferred example may be polyurethane foam or even a combination of different density/ILD polyurethane foams that are laminated together. For example, one may use HR11 Ca Dark Green polyurethane made by NCFI, 2#/ft3, 13 ILD Ca117. Other non-limiting examples may include the following, selected also in conjunction with the turn angle when needed and the desired level of comfort. Several of the more important properties are stated below in density and ILD, for three different examples regarding three different kinds of foam for the Star Chamber air cylinders:

Exemplary Foam Density ILD HR11 Ca Dark  2.0 pounds per cubic foot 13 pounds Green PRS35 Ca Tan 2.25 pounds per cubic foot 35 pounds UC11  1.5 pounds per cubic foot 14 pounds

Examples of particularly suitable foams include polyethylene, polyurethane, polyester, straight chain or cross-linked varieties of each as well as combinations of polyethylene, polyurethane, and polyester foams. Preferably the foam will have a density range of about 1.5 to about 2.5 lbs/ft³ and an IFD/ILD range of about 12 to about 15. The foam can be either an open cell or a closed cell type foam. With an open cell foam, air flows through the foam cells as the air travels from one chamber to another. With a closed cell foam, air on the surface of the foam is allowed to flow between the foam and bladder 200. Upon impact or load, the air contained within the closed cells is also compressed.

The exemplary support structure 216 comprises a length 218, a width 220, a height 222 and has a volume and can assume any shape known to those skilled in the art. Particularly preferable shapes include those comprising projections extending from a central core or central region such as a star or gear shape. Support structure 216 also comprises support structure first face 224 and support structure second face 226. The foam can have either an open or a closed cell structure. In one preferred embodiment, an open cell structure is used. As shown by respective FIGS. 5A-5D, exemplary alternative shapes respectively 217, 219, 221, and 223 of the support structure 216 are envisioned.

As shown by FIG. 6, the exemplary support structure 216 also comprises an inner region generally 228 with support projections 230 extending outwardly from inner region 228. Such support projections 230 preferably define openings generally 232. Openings 232 are unbounded by the support structure 216 in at least one direction. For purposes of example only, when the openings 232 are in the shape of a triangle, the base of the triangle (which would face toward the inner surface of the bladder 200) is open and not enclosed by the support structure 216, while the sides of the triangle are otherwise enclosed by the support structure 216.

The support projections 230 and openings 232 comprise outer region generally 234, which is the region of the bladder comprised of the support projections 230 and the openings 232 they define.

Openings 232 can extend the length of the support structure 216. Each opening 232 is defined by two support projections 230. In an alternative embodiment, openings 232 may only extend partially through a present support structure, such as structure 216 (or any other present embodiments). In a further embodiment, openings 232 may originate at both support structure first end 224 and support structure second end 226, and may be offset with respect to one another as the openings 232 extend the length of the support structure 216.

Support projections 230 have an engaging end 236 located away from the inner region 228 which comprises the portion of the support structure 216 not including the support projections 230 and the openings 232 they define.

In a further embodiment, inner region 228 may define a cavity 238 which can extend throughout the length of support structure 216. Alternatively, cavity 238 may only extend partially along the length of support structure 216. Cavity 238 may be any shape known to those of skill in the art but is representatively illustrated in FIG. 6 as a circle for illustrative purposes only. In a further embodiment, cavity 238 may be present on support structure first face 224 and support structure second face 226, present on one or the other or present on neither yet contained within support structure 216 in a “hollow” configuration.

Support projections 230 also have a support projection base 240 as illustrated by the dashed line PB on FIG. 6 and a support structure body length 241 illustrated by dashed line BL on FIG. 6. In a preferred embodiment, support projections 230 are integral with support structure inner region 228. Support projections 230 also have a support projection body 242 which extends generally away from inner region 228. Support projection body 242 ends with terminal area 244. Terminal area 244 may comprise a point, a convex rounded surface, a concave rounded surface, a flat surface or combinations thereof, or other. For example, in one embodiment wherein support structure 216 comprises five support projections, two may have a terminal area 244 that is a point, one terminal area may be a convex rounded surface, and two terminal areas may be a flat surface.

As shown by FIG. 4, the bladder 200 encloses the support structure 216. The bladder 200 can be made of any suitable material known in the art including but not limited to plastic, polymers, meltblown or spunblown material, cloth, rubber, or coated fabrics. One exemplary embodiment of bladder material may comprise Stevens polyurethane film; ST 2592. Others may so involve, for example, ST3380 and ST3382, all of which have various lists of different characteristic (for example, durometer, permeability, melt point, etc) which may variously be considered by those of ordinary skill in the art whenever implementing particular embodiments in accordance with the present subject matter. Similarly, various thicknesses may be practiced in accordance with the present subject matter, with some preferred examples falling into a range of about 12 mils to about 15 mils. Urethane coated nylon is among some of the preferred embodiment materials while urethane is preferred in some instances because it inherently permits viewing of the star-shaped insert (or other internal component) upon inspection, while urethane coated nylon would not provide such feature. The bladder 200 comprises an outer surface 202, an inner surface 204, a length 206, a height 208, a width 210, and a first end 212 and a second end 214. The bladder 200 may be opaque or clear. In certain embodiments, the bladder 200 has a column shape but may also have a cigar shape, rectangular, or other shape known to those skilled in the art. It is understood that the volume of the bladder 200 will be calculated based on the shape of the particular embodiment being measured as known to those skilled in the art. For purposes of example only, in instances where the shape is columnar, volume will be calculated as pi multiplied by the radius squared multiplied by the length of the column. In rectangular or square embodiments, volume is calculated as length multiplied by width multiplied by height. It is further understood that in some embodiments bladder height and width may be equal or they may be different, e.g., in ellipsoid shaped bladders. Bladder 200 is intended as representing all such variations of the present subject matter.

In one present exemplary embodiment, the support structure first face 224 contacts bladder first end 212, and support structure second face 226 contacts bladder second end 214. In other embodiments, support structure first face 224 and second face 226 do not contact bladder first end 212 and bladder second end 214. In still another embodiments, support structure first face 224 or second face 226, or both, may comprise support projections 230 which extend outward from each face to engage bladder first end 212 and bladder second end 214, respectively. Either first end 212 or second end 214 may have a connection (not shown) as known to those skilled in the art made with a respective section of tubing (not shown). Such air tubing interconnects with the interior of the bladder to facilitate initially establishing air pressure therein and/or later adjusting such amount of air pressure.

Alternatively, bladder 200 may be arranged in series with other bladders with interconnections between bladders 200 to allow air or fluid to pass from one bladder 200 to another in response to pressure applied to the patient support surface. In addition to the numerous support arrangement variations which may be practiced, including longitudinal, lateral, angular, and mixed arrangements of single or multiple air or fluid bladders 200, in accordance with the present subject matter, it is also to be understood that numerous self-adjusting components may be provided in accordance with the present subject matter for use with various such support arrangements. Further, when bladder 200 is used in series with other bladders 200, it is understood that the plurality of bladders 200 are arranged so that preferably they do not contact one another during various loading conditions, though contact may be involved in some instances, when the patient support surface or other embodiment is either loaded or unloaded.

In one present exemplary embodiment, the volume of support structure 216 may comprise substantially all of the volume of bladder 200. In another embodiment, support structure 216 may comprise 90% or less of the volume of bladder 200. In other embodiments, support structure 216 may comprise 80% or less of the volume of bladder 200, 70% or less or even 60% or less of the volume of bladder 200. In one preferred embodiment, it may comprise about 80%. More broadly, as otherwise discussed herein, it is to be understood by those of ordinary skill in the art that the present subject matter is intended as having a foam-to-air ratio relatively as low as possible while still being able to have the foam component to restore the unloaded volume of the tube, which results in varying ratios for particular embodiments depending on their specifics.

The various embodiments of the present subject matter disclosed herein are used to assist with increasing comfort and stability in patient support surfaces using a combination air or fluid filled bladder 200 and internal support structure 216. The present subject matter can be used in conjunction with a method of equalizing pressure over the surface of the body by means of interconnected air or fluid-filled tubes that shift air or fluid from bladders under more pressure to bladders under less pressure. Such functionality allows greater immersion of the body into the mattress, which decreases pressure under any single point, and distributes pressure over as great an area as possible.

The present subject matter allows the support structure 216 to keep the bladder 200 expanded by the support projections 230 contacting the inner surface 204 of the support bladder 200 via terminal area 244. Bladder 200 thus exerts force upon inner surface 204. Accordingly, bladder 200 does not collapse if air pressure in the bladder 200 is reduced. Further, using support structure 216 which contains support structure openings 232, which are defined on either side by support projections 230, one is able to use less foam in constructing the support structure 216 via incorporation of support structure openings 232.

Further, support structure openings 232 in support structure 216 provide several distinct advantages over existing systems. Such advantages may include allowing bladder 200 (which in one exemplary embodiment may be an air filled bladder containing foam support structure 216) to possess the feel and support of an air mattress as known to those skilled in the art while also maintaining the benefits of a foam mattress. Such advantageous performance includes increased structural support as well as protection against the bladder 200 collapsing when air pressure is removed or if the bladder 200 is punctured. Additional advantages include that openings 232 serve to allow air or fluid to move more freely within the bladder 200 as opposed to existing systems where the foam block is a solid construct that essentially fills the interior of the air cylinder used in such devices. In the present subject matter, openings 232, or in alternative embodiments cavity 238 alone or in combination with openings 232, allow air or fluid to move about in the bladder 200 with less restriction.

Air or fluid can move within openings 232 or cavity 238 without necessitating air or fluid flow through the material comprising support structure 216. Such advantageous functionality prevents slowing air or fluid movement which in turn slows the ability of the bladder 200 to react to patient movement or pressure changes.

Embodiments of the present subject matter also help overcome the tendency of existing patient support systems toward “hammocking” wherein pressure accumulates toward the area of least lateral support, often the center of a patient support surface. This results in a hammock effect, which is uncomfortable for a person resting on the mattress. Moreover, when air is let out of existing patient support systems incorporating only air-filled bladders, the entire apparatus collapses and no longer supports the reclining body, the hammock effect being present all the way down through partial deflation. Such characteristic can be undesirable in a mattress because each movement of weight, such as found in a typical person's sleeping pattern, shifts the hammock effect around on the mattress.

Use of the present subject matter would be applicable to all manner of seating arrangements (including partially reclined or angled seating arrangements such as military vehicles designed to withstand acceleration shock). Applicable seating arrangements may include wheelchairs and geriatric care chairs of all type. Consumer seating arrangements may also include ergonomic chairs (such as for office workers) and automobile or transportation vehicle seating devices of all types. In conjunction with such, there could be a particular improvement in rider comfort, especially in long term travel circumstances or otherwise rough ride circumstances such as in trucks or trains.

It will likewise be understood that multiple bladders 200 in accordance with the present subject matter may be so arranged (i.e., combined), as desired, in either seating arrangements or mattress or patient support systems of virtually all types. In conjunction with medical products, such specialized mattresses may include mattresses themselves, or mattress overlays, or mattress replacement systems. The resulting support systems may be specialized for X-ray, operating room, or NMR/MRI technology use. Still further, arrangements thereof may be made for intended use in either intensive care or regular care settings, including home healthcare or nursing home settings. The present subject matter would likewise be applicable to all manner of critical care settings, as well as burn patient settings, emergency room gurneys, and ambulance stretchers.

In addition to the many embodiments referenced above, it is to be further understood that other variations may be practiced so as to combine different features for obtaining bladders for use in patient support surfaces and other supports of types not illustrated. For example, a bladder in accordance with present subject matter can be created with uses a low molecular weight liquid in association with multiple support structures disposed in a bladder. Further yet, the number and method of orienting the bladders may be changed, such as placing bladders alongside and on top of one another for use in a patient support surface. All such variations and modifications are intended to come within the spirit and scope of the present subject matter. Therefore, the spirit and scope of the present subject matter should not be limited to the description of the exemplary presently preferred versions contained herein. 

1. A patient support system for the prevention and treatment of decubitus ulcers, said patient support system comprising: a foam shell defining an internal cavity; a plurality of air cells housed in said internal cavity; and a cover encasing said foam shell; wherein said plurality of air cells respectively each comprises a bladder and an internal support structure comprised of resilient material and only partly in contact with said bladder.
 2. A patient support system as in claim 1, wherein: said bladder comprises an outer and inner surface having a length, height and width, first and second ends, and an internal volume; and said support structure is disposed within said bladder and has a length, width, height, and an inner and outer region.
 3. A patient support system as in claim 2, wherein said outer region includes support projections which define openings in said outer region of said support structure.
 4. A patient support system as in claim 3, wherein said support projections each have an engaging end which contacts said inner surface of said bladder and exerts force upon said inner surface of said bladder, so as to maintain the internal volume of said bladder whenever said patient support system is in a no-load sate.
 5. A patient support system as in claim 2, wherein said support structure comprises in a range generally from about 60% to about 90% of said bladder internal volume.
 6. A patient support system as in claim 2, wherein said support structure comprises one of a single piece or multi-piece construct with support projections extending outwardly from said inner region thereof.
 7. A patient support system as in claim 2, wherein said support structure extends one of the full length of said bladder or extends only partially along the length of said bladder.
 8. A patient support system as in claim 2, further including a plurality of support structures enclosed within respective bladders.
 9. A patient support system as in claim 4, wherein: said support projections extend radially outward from said inner region, spaced either evenly or with varying spacing; and said engaging end of a support projection comprises one of a point, a convex rounded surface, a concave rounded surface, a flat surface, or combinations thereof.
 10. A patient support system as in claim 2, wherein each of said bladders includes fluid comprising at least one of gas, liquids, and relatively viscous liquids.
 11. A patient support system as in claim 2, wherein said support structure includes a cross-section which is one of star shaped, cog or gear shaped, cross shaped, and convex shaped with truncated projections.
 12. A patient support system as set forth in claim 1, wherein: said plurality of air cells are oriented from head-to-foot within said foam shell; said cover includes a mattress topper; and said foam shell is a multi-piece foam shell comprising foam bolsters, a foam header and a foam footer.
 13. A patient support system as set forth in claim 1, further including an airflow unit for providing inflationary airflows to said air cells.
 14. A patient support system as set forth in claim 1, further including a plurality of air tubes interconnected among said air cells, for shifting air from cells under more pressure to cells under less pressure, for equalizing pressure over the surface of a patient received on said patient support system.
 15. A patient support assembly, comprising: plural patient support cylinders; a resilient foam perimeter surrounding said air cylinders; an upper foam topper covering said air cylinders; and a surrounding cover; wherein said cylinders respectively include fluid and foam inserts having support projections supporting associated of said cylinders; and said cylinders are positioned one of generally longitudinally and generally laterally within said resilient foam perimeter.
 16. A patient support assembly as in claim 15, wherein: said cylinders comprise static air cylinders; and said assembly further includes pneumatic valving operatively interconnected to said air cylinders for selectively introducing air and removing air therefrom, so that said air cylinders may be selectively and periodically recharged to a desired initial air pressure while otherwise providing a static, unpowered assembly.
 17. A patient support assembly as in claim 15, wherein said cylinders comprise actively adjustable air cylinders.
 18. A patient support assembly as in claim 15, wherein: said cylinders respectively comprise bladders formed of resilient material; and said support projections have an engaging end which contacts the inner surface of said bladders and exerts force upon said respective inner surfaces so as to maintain an internal volume of said bladders in a no-load state.
 19. A support system including a plurality of fluid receiving cells, with each of said cells including at least one foam insert having internal support structure only partly in contact with an associated cell.
 20. A support system as in claim 19, wherein: said support structure comprises in a range generally from about 60% to about 90% of the interior of an associated cell; and said support structure includes a cross-section which is one of star shaped, cog or gear shaped, cross shaped, and convex shaped with truncated projections.
 21. A support system as in claim 19, wherein said fluid comprises at least one of gas, liquids, and relatively viscous liquids.
 22. A support system as in claim 19, further including: a foam shell surrounding said plurality of fluid receiving cells; and a cover encasing said foam shell; wherein said support system comprises one of a mattress, a mattress overlay, an ergonomic chair, a car seat, and a packaging arrangement for products. 